// tutorial04.c
// A pedagogical video player that will stream through every video frame as fast as it can,
// and play audio (out of sync).
//
// Code based on FFplay, Copyright (c) 2003 Fabrice Bellard, 
// and a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de)
// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1
// Use
//
//gcc -o tutorial04 tutorial04.c -lavutil -lavformat -lavcodec -lz -lavutil -lm -lpthread -lswscale -lSDL
//  `sdl-config --cflags --libs`
// to build (assuming libavformat and libavcodec are correctly installed, 
// and assuming you have sdl-config. Please refer to SDL docs for your installation.)
//
// Run using
// tutorial04 myvideofile.mpg
//
// to play the video stream on your screen.




#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h> 

#include <SDL/SDL.h>
#include <SDL/SDL_thread.h>
#include <assert.h>


#ifdef __MINGW32__
#undef main /* Prevents SDL from overriding main() */
#endif

#include <stdio.h>
#include <math.h>

#define SDL_AUDIO_BUFFER_SIZE 1024

#define MAX_AUDIOQ_SIZE (5 * 16 * 1024)
#define MAX_VIDEOQ_SIZE (5 * 256 * 1024)

#define FF_ALLOC_EVENT   (SDL_USEREVENT)
#define FF_REFRESH_EVENT (SDL_USEREVENT + 1)
#define FF_QUIT_EVENT (SDL_USEREVENT + 2)

#define VIDEO_PICTURE_QUEUE_SIZE 4

typedef struct PacketQueue 
{
	AVPacketList *first_pkt, *last_pkt;
	int nb_packets;
	int size;
	SDL_mutex *mutex;
	SDL_cond *cond;
} PacketQueue;


typedef struct VideoPicture 
{
	SDL_Overlay *bmp;
	int width, height; /* source height & width */
	int allocated;
} VideoPicture;

typedef struct VideoState 
{
	AVFormatContext *pFormatCtx;
	int             videoStream, audioStream;
	AVStream        *audio_st;
	PacketQueue     audioq;
	uint8_t         audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2];
	unsigned int    audio_buf_size;
	unsigned int    audio_buf_index;
	AVPacket        audio_pkt;
	AVPacket        audio_pkt_temp;
	AVStream        *video_st;
	PacketQueue     videoq;

	VideoPicture    pictq[VIDEO_PICTURE_QUEUE_SIZE];
	int             pictq_size, pictq_rindex, pictq_windex;
	SDL_mutex       *pictq_mutex;
	SDL_cond        *pictq_cond;

	SDL_Thread      *parse_tid;
	SDL_Thread      *video_tid;

	char            filename[1024];
	int             quit;
} VideoState;

SDL_Surface     *screen;

/* Since we only have one decoding thread, the Big Struct
   can be global in case we need it. */
VideoState *global_video_state;

int img_convert(AVPicture *dst, int dst_pix_fmt,  
                const AVPicture *src, int src_pix_fmt,  
                int src_width, int src_height)  
{  
    int w;  
    int h;  
    static struct SwsContext *pSwsCtx;  

  
    w = src_width;  
    h = src_height;  
    pSwsCtx = sws_getContext(w, h, src_pix_fmt,  
                            w, h, dst_pix_fmt,  
                            SWS_BICUBIC, NULL, NULL, NULL);  
  
    sws_scale(pSwsCtx, (const uint8_t* const*)src->data, src->linesize,  
            0, h, dst->data, dst->linesize);  
 
 
    return 0;  
} 


void packet_queue_init(PacketQueue *q) 
{
	memset(q, 0, sizeof(PacketQueue));
	q->mutex = SDL_CreateMutex();
	q->cond = SDL_CreateCond();
}
int packet_queue_put(PacketQueue *q, AVPacket *pkt) 
{
	AVPacketList *pkt1;
	if(av_dup_packet(pkt) < 0) 
	{
		return -1;
	}
	pkt1 = av_malloc(sizeof(AVPacketList));
	if (!pkt1)
		return -1;
	pkt1->pkt = *pkt;
	pkt1->next = NULL;

	SDL_LockMutex(q->mutex);

	if (!q->last_pkt)
		q->first_pkt = pkt1;
	else
		q->last_pkt->next = pkt1;
	q->last_pkt = pkt1;
	q->nb_packets++;
	q->size += pkt1->pkt.size;
	SDL_CondSignal(q->cond);

	SDL_UnlockMutex(q->mutex);
	return 0;
}
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block)
{
	AVPacketList *pkt1;
	int ret;

	SDL_LockMutex(q->mutex);

	for(;;)
	{ 
		if(global_video_state->quit)
		{
			ret = -1;
			break;
		}

		pkt1 = q->first_pkt;
		if (pkt1)
		{
			q->first_pkt = pkt1->next;
			if (!q->first_pkt)
				q->last_pkt = NULL;
			q->nb_packets--;
			q->size -= pkt1->pkt.size;
			*pkt = pkt1->pkt;
			av_free(pkt1);
			ret = 1;
			break;
		}
		else if(!block)
		{
			ret = 0;
			break;
		}
		else
		{
			SDL_CondWait(q->cond, q->mutex);
		}
	}
	SDL_UnlockMutex(q->mutex);
	return ret;
}

int audio_decode_frame(VideoState *is, uint8_t *audio_buf, int buf_size)
{
	int len1, data_size;
	AVPacket *pkt = &is->audio_pkt;
	AVPacket *pkt_temp = &is->audio_pkt_temp;

	for(;;)
	{
		while(pkt_temp->size > 0)
		{
			data_size = buf_size;
			len1 = avcodec_decode_audio3(is->audio_st->codec, 
					  (int16_t *)audio_buf, &data_size,  pkt_temp);
			if(len1 < 0)
			{
				/* if error, skip frame */
				pkt_temp->size = 0;
				break;
			}
			pkt_temp->data += len1;
			pkt_temp->size -= len1;
			assert(pkt_temp->size==0);
			if(data_size <= 0)
			{
				/* No data yet, get more frames */
				continue;
			}
			/* We have data, return it and come back for more later */
			return data_size;
		}
		if(pkt->data)
			av_free_packet(pkt);

		if(is->quit)
		{
			return -1;
		}
		/* next packet */
		if(packet_queue_get(&is->audioq, pkt, 1) < 0)
		{
			return -1;
		}
		//printf("pkt->size=%d\n", pkt->size);
		*pkt_temp = *pkt;
	}
}

void audio_callback(void *userdata, Uint8 *stream, int len)
{
	VideoState *is = (VideoState *)userdata;
	int len1, audio_size;
	//printf("in audio_callback len=%d\n", len);

	while(len > 0)
	{
		if(is->audio_buf_index >= is->audio_buf_size)
		{
			/* We have already sent all our data; get more */
			audio_size = audio_decode_frame(is, is->audio_buf, sizeof(is->audio_buf));
			//printf("audio_size =%d\n", audio_size);
			if(audio_size < 0)
			{
				/* If error, output silence */
				is->audio_buf_size = 1024;
				memset(is->audio_buf, 0, is->audio_buf_size);
			}
			else
			{
				is->audio_buf_size = audio_size;
			}
			is->audio_buf_index = 0;
		}
		len1 = is->audio_buf_size - is->audio_buf_index;
		//printf("len1 = %d\n", len1);
		if(len1 > len)
			len1 = len;
		memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1);
		len -= len1;
		stream += len1;
		is->audio_buf_index += len1;
	}
}

static Uint32 sdl_refresh_timer_cb(Uint32 interval, void *opaque)
{
	SDL_Event event;
	event.type = FF_REFRESH_EVENT;
	event.user.data1 = opaque;
	SDL_PushEvent(&event);
	return 0; /* 0 means stop timer */
}

/* schedule a video refresh in 'delay' ms */
static void schedule_refresh(VideoState *is, int delay)
{
	SDL_AddTimer(delay, sdl_refresh_timer_cb, is);
}

void video_display(VideoState *is)
{
	SDL_Rect rect;
	VideoPicture *vp;
	AVPicture pict;
	float aspect_ratio;
	int w, h, x, y;
	int i;

	vp = &is->pictq[is->pictq_rindex];
	if(vp->bmp)
	{
		if(is->video_st->codec->sample_aspect_ratio.num == 0)
		{
			aspect_ratio = 0;
		}
		else
		{
			aspect_ratio = av_q2d(is->video_st->codec->sample_aspect_ratio) *
			is->video_st->codec->width / is->video_st->codec->height;
		}
		
		if(aspect_ratio <= 0.0)
		{
			aspect_ratio = (float)is->video_st->codec->width /
			(float)is->video_st->codec->height;
		}
		
		h = screen->h;
		w = ((int)rint(h * aspect_ratio)) & -3;
		if(w > screen->w)
		{
			w = screen->w;
			h = ((int)rint(w / aspect_ratio)) & -3;
		}
		x = (screen->w - w) / 2;
		y = (screen->h - h) / 2;

		rect.x = x;
		rect.y = y;
		rect.w = w;
		rect.h = h;
						
		SDL_DisplayYUVOverlay(vp->bmp, &rect);
	}
}

void video_refresh_timer(void *userdata)
{
	VideoState *is = (VideoState *)userdata;
	VideoPicture *vp;

	if(is->video_st)
	{
		if(is->pictq_size == 0)
		{
			//printf("no picture\n");
			schedule_refresh(is, 1);
		}
		else
		{
			vp = &is->pictq[is->pictq_rindex];
			/* Now, normally here goes a ton of code
			about timing, etc. we're just going to
			guess at a delay for now. You can
			increase and decrease this value and hard code
			the timing - but I don't suggest that ;)
			We'll learn how to do it for real later.
			*/
			schedule_refresh(is, 72);

			/* show the picture! */
			video_display(is);

			/* update queue for next picture! */
			if(++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE)
			{
				is->pictq_rindex = 0;
			}
			SDL_LockMutex(is->pictq_mutex);
			is->pictq_size--;
			SDL_CondSignal(is->pictq_cond);
			SDL_UnlockMutex(is->pictq_mutex);
		}
	}
	else 
	{
		schedule_refresh(is, 100);
	}
}
      
void alloc_picture(void *userdata)
{
	VideoState *is = (VideoState *)userdata;
	VideoPicture *vp;

	vp = &is->pictq[is->pictq_windex];
	if(vp->bmp)
	{
		// we already have one make another, bigger/smaller
		SDL_FreeYUVOverlay(vp->bmp);
	}
	// Allocate a place to put our YUV image on that screen
	vp->bmp = SDL_CreateYUVOverlay(is->video_st->codec->width,
			is->video_st->codec->height,
			SDL_YV12_OVERLAY,
			screen);
	vp->width = is->video_st->codec->width;
	vp->height = is->video_st->codec->height;

	SDL_LockMutex(is->pictq_mutex);
	vp->allocated = 1;
	SDL_CondSignal(is->pictq_cond);
	SDL_UnlockMutex(is->pictq_mutex);

}

int queue_picture(VideoState *is, AVFrame *pFrame)
{
	VideoPicture *vp;
	int dst_pix_fmt;
	AVPicture pict;

	/* wait until we have space for a new pic */
	SDL_LockMutex(is->pictq_mutex);
	while(is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE && !is->quit)
	{
		//printf(" picture quene is full\n");
		SDL_CondWait(is->pictq_cond, is->pictq_mutex);
	}
	SDL_UnlockMutex(is->pictq_mutex);

	if(is->quit)
		return -1;

	// windex is set to 0 initially
	vp = &is->pictq[is->pictq_windex];

	/* allocate or resize the buffer! */
	if(!vp->bmp ||
		vp->width != is->video_st->codec->width ||
		vp->height != is->video_st->codec->height)
	{
		SDL_Event event;

		vp->allocated = 0;
		/* we have to do it in the main thread */
		event.type = FF_ALLOC_EVENT;
		event.user.data1 = is;
		SDL_PushEvent(&event);

		/* wait until we have a picture allocated */
		SDL_LockMutex(is->pictq_mutex);
		while(!vp->allocated && !is->quit)
		{
			SDL_CondWait(is->pictq_cond, is->pictq_mutex);
		}
		SDL_UnlockMutex(is->pictq_mutex);
		if(is->quit)
		{
			return -1;
		}
	}
	
	/* We have a place to put our picture on the queue */
	if(vp->bmp)
	{

		SDL_LockYUVOverlay(vp->bmp);

		dst_pix_fmt = PIX_FMT_YUV420P;
		/* point pict at the queue */

		pict.data[0] = vp->bmp->pixels[0];
		pict.data[1] = vp->bmp->pixels[2];
		pict.data[2] = vp->bmp->pixels[1];

		pict.linesize[0] = vp->bmp->pitches[0];
		pict.linesize[1] = vp->bmp->pitches[2];
		pict.linesize[2] = vp->bmp->pitches[1];

		// Convert the image into YUV format that SDL uses
		img_convert(&pict, dst_pix_fmt,
			(AVPicture *)pFrame, is->video_st->codec->pix_fmt, 
			is->video_st->codec->width, is->video_st->codec->height);

		SDL_UnlockYUVOverlay(vp->bmp);
		/* now we inform our display thread that we have a pic ready */
		if(++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE)
		{
			is->pictq_windex = 0;
		}
		SDL_LockMutex(is->pictq_mutex);
		is->pictq_size++;
		SDL_UnlockMutex(is->pictq_mutex);
	}
	return 0;
}

int video_thread(void *arg)
{
	VideoState *is = (VideoState *)arg;
	AVPacket pkt1, *packet = &pkt1;
	int len1, frameFinished;
	AVFrame *pFrame;

	pFrame = avcodec_alloc_frame();

	for(;;)
	{
		if(packet_queue_get(&is->videoq, packet, 1) < 0)
		{
			// means we quit getting packets
			break;
		}
		// Decode video frame
		len1 = avcodec_decode_video2(is->video_st->codec, pFrame, &frameFinished, packet);

		// Did we get a video frame?
		if(frameFinished)
		{
			if(queue_picture(is, pFrame) < 0)
			{
				break;
			}
		}
		av_free_packet(packet);
	}
	av_free(pFrame);
	return 0;
}

int stream_component_open(VideoState *is, int stream_index)
{
	AVFormatContext *pFormatCtx = is->pFormatCtx;
	AVCodecContext *codecCtx;
	AVCodec *codec;
	SDL_AudioSpec wanted_spec, spec;

	if(stream_index < 0 || stream_index >= pFormatCtx->nb_streams)
	{
		return -1;
	}

	// Get a pointer to the codec context for the video stream
	codecCtx = pFormatCtx->streams[stream_index]->codec;

	if(codecCtx->codec_type == AVMEDIA_TYPE_AUDIO)
	{
		// Set audio settings from codec info
		wanted_spec.freq = codecCtx->sample_rate;
		wanted_spec.format = AUDIO_S16SYS;
		wanted_spec.channels = codecCtx->channels;
		wanted_spec.silence = 0;
		wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
		wanted_spec.callback = audio_callback;
		wanted_spec.userdata = is;

		if(SDL_OpenAudio(&wanted_spec, &spec) < 0)
		{
			fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
			return -1;
		}
	}
	codec = avcodec_find_decoder(codecCtx->codec_id);
	if(!codec || (avcodec_open(codecCtx, codec) < 0))
	{
		fprintf(stderr, "Unsupported codec!\n");
		return -1;
	}

	switch(codecCtx->codec_type)
	{
		case AVMEDIA_TYPE_AUDIO:
			is->audioStream = stream_index;
			is->audio_st = pFormatCtx->streams[stream_index];
			is->audio_buf_size = 0;
			is->audio_buf_index = 0;
			memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
			packet_queue_init(&is->audioq);
			SDL_PauseAudio(0);
			break;
		case AVMEDIA_TYPE_VIDEO:
			is->videoStream = stream_index;
			is->video_st = pFormatCtx->streams[stream_index];

			packet_queue_init(&is->videoq);
			is->video_tid = SDL_CreateThread(video_thread, is);
			break;
		default:
			break;
	}
}

int decode_interrupt_cb(void)
{
	return (global_video_state && global_video_state->quit);
}

int decode_thread(void *arg)
{
	VideoState *is = (VideoState *)arg;
	AVFormatContext *pFormatCtx;
	AVPacket pkt1, *packet = &pkt1;

	int video_index = -1;
	int audio_index = -1;
	int i;

	is->videoStream=-1;
	is->audioStream=-1;

	global_video_state = is;
	// will interrupt blocking functions if we quit!
	//url_set_interrupt_cb(decode_interrupt_cb);

	// Open video file
	pFormatCtx = avformat_alloc_context();
	if(avformat_open_input(&pFormatCtx, is->filename, NULL, NULL)!=0)
		return -1; // Couldn't open file

	is->pFormatCtx = pFormatCtx;

	// Retrieve stream information
	if(av_find_stream_info(pFormatCtx)<0)
		return -1; // Couldn't find stream information

	// Dump information about file onto standard error
	av_dump_format(pFormatCtx, 0, is->filename, 0);

	// Find the first video stream
	for(i=0; i<pFormatCtx->nb_streams; i++)
	{
		if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO && video_index<0)
		{
			video_index=i;
		}
		if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO && audio_index < 0)
		{
			audio_index=i;
		}
	}
	
	if(audio_index >= 0)
	{
		stream_component_open(is, audio_index);
	}
	if(video_index >= 0)
	{
		stream_component_open(is, video_index);
	}   

	if(is->videoStream < 0 || is->audioStream < 0)
	{
		fprintf(stderr, "%s: could not open codecs\n", is->filename);
		goto fail;
	}

	// main decode loop
	for(;;)
	{
		if(is->quit)
		{
			break;
		}
		//printf("is->videoq.size =%d\n", is->videoq.size);
		// seek stuff goes here
		if(is->audioq.size > MAX_AUDIOQ_SIZE || is->videoq.size > MAX_VIDEOQ_SIZE)
		{
			//if(is->videoq.size > MAX_VIDEOQ_SIZE)
			//	printf("video packet quene is full\n");
			//if(is->audioq.size > MAX_AUDIOQ_SIZE)
			//	printf("audeo packet quene is full\n");
			SDL_Delay(10);
			continue;
		}
		
		if(av_read_frame(is->pFormatCtx, packet) < 0)
		{
			if(pFormatCtx->pb && pFormatCtx->pb->error)
			{
				SDL_Delay(100); /* no error; wait for user input */
				continue;
			}
			else
			{
				break;
			}
		}
		// Is this a packet from the video stream?
		if(packet->stream_index == is->videoStream)
		{
			packet_queue_put(&is->videoq, packet);
		}
		else if(packet->stream_index == is->audioStream)
		{
			packet_queue_put(&is->audioq, packet);
		}
		else
		{
			av_free_packet(packet);
		}
	}
	/* all done - wait for it */
	while(!is->quit)
	{
		SDL_Delay(100);
	}

fail:
	if(1)
	{
		SDL_Event event;
		event.type = FF_QUIT_EVENT;
		event.user.data1 = is;
		SDL_PushEvent(&event);
	}
	return 0;
}

int main(int argc, char *argv[])
{
	SDL_Event       event;

	VideoState      *is;

	is = av_mallocz(sizeof(VideoState));

	if(argc < 2)
	{
		fprintf(stderr, "Usage: test <file>\n");
		exit(1);
	}
	// Register all formats and codecs
	av_register_all();

	if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER))
	{
		fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
		exit(1);
	}

	// Make a screen to put our video
#ifndef __DARWIN__
	    screen = SDL_SetVideoMode(640, 480, 0, 0);
#else
	    screen = SDL_SetVideoMode(640, 480, 24, 0);
#endif
	if(!screen)
	{
		fprintf(stderr, "SDL: could not set video mode - exiting\n");
		exit(1);
	}

	av_strlcpy(is->filename, argv[1], sizeof(is->filename));

	is->pictq_mutex = SDL_CreateMutex();
	is->pictq_cond = SDL_CreateCond();

	schedule_refresh(is, 40);

	is->parse_tid = SDL_CreateThread(decode_thread, is);
	if(!is->parse_tid)
	{
		av_free(is);
		return -1;
	}
	for(;;)
	{

		SDL_WaitEvent(&event);
		switch(event.type)
		{
			case FF_QUIT_EVENT:
			case SDL_QUIT:
				is->quit = 1;
				SDL_Quit();
				return 0;
				break;
			case FF_ALLOC_EVENT:
				alloc_picture(event.user.data1);
				break;
			case FF_REFRESH_EVENT:
				video_refresh_timer(event.user.data1);
				break;
			default:
				break;
		}
	}
	return 0;
}
